Brown the mushrooms in the butter, then deglaze the pan with the wine. Reduce the wine by half, then whisk in the flour. Add in the chicken stock and cook until slightly thickened. Season as needed.
Add the lemon juice and shrimp and continue cooking until the shrimp are done. Stir in the spinach and parsley and cook until the spinach wilts slightly.
Plate the pasta, top with the shrimp mixture and serve.